The fabrication of organic thin film transistors with highly reproducible characteristics presents a very challenging task. We have prepared and analyzed model pentacene thin film transistors under ultra-high vacuum conditions, employing surface analytical tools and methods. Intentionally contaminating the gold contacts and SiO2 channel area with carbon through repeated adsorption, dissociation...

Gaseous, ionized polycyclic aromatic hydrocarbons (PAHs) are thought to be responsible for a very common family of interstellar infrared emission bands. Unfortunately, very little infrared spectroscopic data are available on ionized PAHs. Here we present the near- and mid-infrared spectra of the polyacene cations anthracene, tetracene, and pentacene. We also report the vibrational frequencie...

Pentacene is one of the most studied organic semiconducting materials. While many aspects of the film formation have already been identified in very thin films, this study provides new insight into the transition from the metastable thin-film phase to bulk phase polymorphs. This study focuses on the growth behavior of pentacene within thin films as a function of film thickness ranging from 20 t...

The outstanding performance of pentacene-based molecules in molecular electronics, as well as the predicted enhanced semiconducting properties of extended acenes, have stimulated the development of new synthetic methods and functionalization strategies for the preparation of stable and soluble acenes larger than tetracene with the aim of obtaining improved functional materials.

The results of a study the effect annealing at 150^oC in an inert atmosphere (Ar + 5% H 2 ) on electrical properties organic field-effect transistors based pentacene are presented. Crystalline films with thickness 95±5 nm were obtained using thermal vacuum deposition. transfer and output characteristics before after for 15 hours investigated. It was found that as result heat treatment, hole mob...

6,13-Bis(triisopropylsilylethynyl) (TIPS)-pentacene has proven to be a promising soluble p-type material for organic thin film transistors as well as for photovoltaics. In this work, we show that adding electron-withdrawing nitrile functional groups to TIPS-pentacene turns it into an n-type material, which can be used as an acceptor for organic solar cells. Several new cyanopentacenes with diff...

In this work we present in situ electrical and surface analytical, as well as ex situ atomic force microscopy (AFM) studies on temperature and surface condition induced pentacene layer growth modifications, leading to the selection of optimized deposition conditions and entailing performance improvements. We prepared p++-silicon/silicon dioxide bottom-gate, gold bottom-contact transistor sample...

A simple three-state model for the dynamics of the singlet fission (SF) process is developed. The model facilitates the analysis of the relative significance of different factors, such as electronic energies, couplings, and the entropic contributions. The entropic contributions to the rates are important; they drive the SF process in endoergic cases (such as tetracene). The anticipated magnitud...

High-performance pentacene field-effect transistors have been fabricated using Al2O3 as a gate dielectric material grown by atomic layer deposition (ALD). Hole mobility values of 1.5 ± 0.2 cm/V s and 0.9 ± 0.1 cm/V s were obtained when using heavily n-doped silicon (n-Si) and ITO-coated glass as gate electrodes, respectively. These transistors were operated in enhancement mode with a zero turn-...